Deep vein thrombosis, also known as DVT, is a serious and potentially life-threatening disorder. The physiological cause of this disorder is lack of adequate blood circulation in the lower extremities. The lack of movement of venous blood can cause clots to form, which may cause blockages in the local blood vessels, or in more serious situations, may lodge in the lungs or heart and cause critical blockages which can be life-threatening.
A large number of medical research studies have shown that deep vein thrombosis can be prevented by enhancing or accelerating the return of venous blood from the lower extremities. A common and accepted method for accelerating venous blood return from the lower limbs is pneumatic compression applied to the sole of the foot and/or the calf muscle of the leg. This form of treatment is commonly referred to as “compression therapy,” and is performed using a compression device, which feeds compressed air to a garment or “sleeve” containing one or more cells which inflate and deflate, alternately applying and releasing pressure to the patient's lower extremities.
In hospitals, there are many devices of this kind, and there are compression therapy usage protocols for patients who are hospitalized for operative procedures or have other risk factors for developing deep vein thrombosis. The compression therapy devices may be used 24 hours a day for the entire hospitalization period. Clinical studies have shown that the effectiveness of such devices is primarily determined by patient and staff compliance, which in turn is affected by ease of use and patient comfort. The usage of such devices is also determined by economic factors such as cost of the device and garments as opposed to pharmaceutical interventions such as heparin.
U.S. Pat. No. 4,013,069 describes compression sleeves made of interior impervious sheets and one or more sheets of soft flexible material for covering the outside of the impervious sheets adjacent the patient's leg. The outer sheets may be made of any suitable material, such as TYVEK™, and they provide an aesthetically pleasing and comfortable outer surface for the sleeve. The outer sheets may be attached to the internal sheets by suitable means, such as stitches along the side and end edges. The sleeves may have a plurality of hook and loop strips to releasably secure the sleeves about the patient's legs.
U.S. Pat. No. 4,066,084 describes a cuff comprising a piece of stable fabric or plastic material of soft but not elastic quality, in the shape of a trapezium, the two non-parallel sides having the same length. The two non-parallel sides are provided with a divisible zip fastener, by means of which the cuff can be shaped to a slightly tapered cylinder fitting a patient's limb. On one side of the form-stable material, a number of elongated inflatable sections are provided arranged parallel to the parallel sides of the trapezium. These sections are manufactured of an elastic, strong plastic material, rubber or other air impervious material. The sections may also consist of balloons inserted in pockets in the cuff.
U.S. Pat. No. 4,338,923 describes a sleeve wrappable about the body part to be treated, made in the form of a substantially flat inflatable band divided into a plurality of internal inflatable cells extending annularly around the sleeve, in partially overlapping relationship. The band is made of three strips of resilient sheet material bonded to each other along spaced bond lines to define the partially overlapping inflatable cells.
The above-described sleeves for compression therapy are of durable construction and constitute a constant part of the massaging device that is used multiple times with different patients, mostly as physical therapy for chronic venous and lymphatic disorders.
When these devices are used as prophylaxis for deep vein thrombosis, either in the operating theater or during the recovery period, the specific needs of the hospital market are for disposable, one-time or one-patient use sleeves. Such made from PVC fabric are manufactured by the Kendall Co. (Tyco) as well as by other major manufacturers. However, the cost of these sleeves is still high, and hospitals have had to reprocess and reuse these so-called “disposable” sleeves in an attempt to cut expenses. In addition, PVC is now considered an environmentally “unfriendly” material, and its use has been curtailed in many countries because of concerns of carcinogenicity. The PVC outer layer also prevents normal evaporation of perspiration, causing discomfort to the patient.